【玩法设计】以物易物：定向换物的双向确认设计

---挂出换物需求：我的物品换想要的物品
function Swap.list(actor, slot, wantItem, wantCount)
    local item = actor.bag[slot]
    if not item or item.bind then return false, "绑定物品不可交换" end
    swapBoard[#swapBoard + 1] = {
        owner = actor:GetID(), give = item, giveSlot = slot,
        want = wantItem, wantN = wantCount, at = os.time(),
    }
    sendmsg(actor, 1, "换物挂单已发布")
    return true
end

---换物的双向确认
function Swap.confirm(actor, swapId)
    local swap = swapBoard[swapId]
    if not swap or swap.done then return false, "挂单已失效" end
    if swap.owner == actor:GetID() then return false, "不能与自己的挂单交换" end
    if getbagitemcount(actor, swap.want, 0) < swap.wantN then
        return false, "缺少对方想要的物品"
    end
    -- 扣双方的物品
    delitembymakeindex(swap.owner, swap.give.makeindex, 1, "以物易物换出")
    local give = actor.bag[swap.wantSlot]
    actor.bag[swap.wantSlot] = nil
    -- 双向发货
    sendmail("#" .. getname(swap.owner), 8001, "以物易物成交", "换入了对方想要的物品", item2reward(give))
    giveitem(actor, swap.give, 1, 1, "以物易物换入")
    swap.done = true
    TradeLog.write("swap", actor:GetID(), swap.owner, swap.give.id, swap.wantN)
    return true
end